Apparatus for producing moving shadow reference lines



A. H. COOPER July 14, 1970 APPARATUS FOR PRODUCING MOVING SHADOW REFERENCE LINES Filed May 6. 1968 INVENTOR fllden H.Cooper H H u H H .w

United States Patent U.S. Cl. 356-200 3 Claims ABSTRACT OF THE DISCLOSURE Apparatus is provided for producing moving shadow reference lines on work moving at a corresponding speed on a conveyor positioned a spaced distance from the apparatus, thereby enabling marking or otherwise processing the work in transit and in accurately defined locations.

This invention relates to apparatus for producing moving shadow reference lines on work conveyed at a predetermined lineal speed on a conveyor positioned a spaced distance from the apparatus. It pertains particularly to apparatus for producing moving shadow reference lines on plywood veneer being fed to a clipper, the reference lines being useful in making the veneer in locations controlling the operation of the clipper.

Situations frequently arise wherein it is necessary or desirable to mark or otherwise process, in accurately determined locations, work being conveyed continuously past an operators station.

Such a situation exists in the plywood industry in which logs are reduced in a plywood lathe to a continuous but imperfect strip of veneer. To eliminate the imperfections, consisting of knot holes, decayed areas and split areas, it is customary to clip the rapidly moving sheet in front of and behind each imperfection. This produces a plurality of veneer pieces some of which are used in the plywood manufacturing operation and others, which contain imperfections, are discarded.

The veneer being fed to the clipper moves at a high rate of speed past an operator who marks it marginally in front of and behind each imperfection. These marks then actuate the clipper photo-electrically or otherwise to eliminate the area containing the imperfection.

A difficulty inherent in this sequence resides in the fact that the plywood sheet is 8 feet or more in width and is moving at a lineal speed of up to 300 feet per minute. Consequently, it is difficult for the operator to project the line of imperfection to the margin of the sheet with a high degree of accuracy.

The necessary consequence of this situation is that he makes his marks substantially in front of or substantially behind each imperfection so that he will be sure to include it in the rejected piece. This in turn results in including a substantial quantity of usable material in the rejected veneer.

It is the general purpose of the present invention to provide apparatus which will produce shadow reference lines on wood veneers or other work, which reference lines move at a speed synchronized with the lineal speed of the work so that they may be used to project the 10- cations of the imperfections to the margins of the work and enable the operator to place his marks or otherwise process the work with a high degree of accuracy.

It is a further object of the present invention to provide apparatus for producing moving shadow reference lines on plywood veneers being fed to a clipper which apparatus is highly accurate, subject to precise adjustment and control, simple in its construction and operation, and adaptable to installation on a conventional plywood line without difficult modification or alteration thereof.

The manner in which the foregoing and other objects of this invention are accomplished will be apparent from the accompanying specification and claims considered together with the drawings, wherein:

FIG. 1 is a schematic view in side elevation of a plywood line illustrating the application of the herein described apparatus for producing moving shadow reference lines on the work;

FIGS. 2 and 3 are views in end and side elevation respectively, both partl broken away to show interior c0nstruction, and further illustrating the apparatus;

FIG. 4 is a fragmentary detail view looking in the direction of the arrows of line 4-4 of FIG. 3; and illustrating the construction of the drive for the apparatus; and

FIG. 5 is a fragmentary plan view looking in the direction of the arrows of line 55 of FIG. 1 and illustrating one application of the apparatus.

In its broad concept, the presently described apparatus for producing moving shadow reference lines on plywood veneers or other work conveyed at a predetermined lineal speed on a conveyer comprises a shielded housing open at the side adjacent the work a spaced distance therefrom. A flexible endless drive is mounted in the housing in a plane parallel to the motion of the work.

A plurality of fixed, parallel rods are mounted on the drive in a predetermined spacing normal to the direction of motion of the work. A light source is mounted in the housing behind the rods. It generates shadow lines which are projected on the work.

Motor means are connected to the drive for driving it and the rods mounted thereon at a speed correlated with the speed of the Work. As a consequence, an operator is able to mark or otherwise process the work marginally with a high degree of accuracy with reference to imperfections or other areas of interest located centrally on the work.

Considering the foregoing in greater detail and with particular reference to the drawings:

FIG. 1 illustrates schematically the application of the herein described apparatus to the projection of moving shadow reference lines on the surface of freshly cut plywood veneer being fed to a clipper.

In this operation a log 10 mounted in a plywood lathe is reduced by a knife 12 to a continuous strip of veneer 14. The strip is deposited on a conveyer 16 moving at a high rate of speed, i.e. a speed of up to 300 feet per minute or even more.

The conveyer drive includes endless chains mounted on idler sprockets 18 and driven at a uniform predetermined rate of speed by drive sprockets 20. The conveyer drives the sheet into a veneer clipper 22 which, as described above, clips the moving sheet laterally as required to divide it into sections which are free of imperfections, and accordingly acceptable, and sections which contain knot holes, rotten areas, splits and other imperfections, indicated schematically at 24 of FIG. 5, and which accordingly, are rejectable.

To accomplish this purpose an operator is stationed at inspection and marking station 0 just ahead of the clipper. His function is to place on the rapidly traveling sheet index marks 26, FIG. 5, marking the location of the imperfections 24. These marks trigger photo-electrically or otherwise operation of clipper 22 so that the sheet is severed laterally at the location of the marks.

However, since the sheet is moving very rapidly and since it is 8 feet or more in width, it is difiicult for the operator to determine the exact marginal location on which to make his marks. As a consequence he is prone to over estimate or under estimate with waste of wood in the event of overestimation and increase in rejects in the event of under estimation.

This difliculty is overcome by the inclusion of the ap paratus of my invention in the veneer producing line.

The apparatus, indicated collectively at 30, is secured at the operators station to ceiling structural members 32. It comprises a housing or light box 34, the lower side of which is open, i.e. the side. adjacent veneer 14.

Housing 34 contains a light source 36 supported centrally within on a bracket 38 and connected to the house electric line by means of wires 40. In a marking apparatus to be used in a conventional plywood mill, a 200 watt, clear, vertical element electric lamp suffices.

Light source 36 is used to generate a moving grid of shadow reference lines by mounting within housing 34 a drive which supports a plurality of spaced, shadow-casting bars or rods.

In the illustrated form of the invention, the drive consists of an endless drive chain 42 which engages a drive sprocket 44 keyed to a drive shaft 46. One end of drive shaft 46 extends outwardly through housing 34 and mounts a sprocket 48. The latter sprocket meshes with one end of an endless chain 50, the other end of which is mounted on an idler sprocket-assembly 52. A drive sprocket 54 mounted on the shaft which mounts drive sprocket 20 engages chain 50. In this manner drive sprocket 44, which drives chain 42, is driven synchronously with the conveyor.

Chain 42 is mounted along one wall of housing 34 in such a manner as to provide a working stretch opposite the open end of the housing.

Shaft 46 and idler sprocket-shaft assemblies 58, 60, 62, which also engage the chain, are mounted rotatably at the four corners of the housing on one side thereof. A cooperating chain 42a is mounted similarly on the opposite side of the housing, parallel to chain 42. Both chains are arranged so that their planes parallel the direction of movement of conveyer 16.

As shown particularly in FIG. 4, chains 42, 42a support between them a plurality of shadow line-generating rods or bars 66. The ends of these rods are received in sleeves 68 which are riveted or otherwise fastened to tabs 70 extending laterally from the side plates of chains 42, 42a. Keepers 72 are swaged or staked on the rods to locate the rods.

The rods are arranged parallel to each other in a direction which is substantially normal to the planes of chains 42, 42a, and hence to the direction of motion of conveyer 16 and veneer 14 thereon.

Bars 66 have a width determined by the width of the shadow lines to be cast. The spacing between the bars is predetermined to define the spacing between the shadow lines. In a typical situation, where the lower end of housing 34 is located four feet above a veneer conveyer 16, rods 6 may have diameters of Ms inch and spacings of 1 inch on centers.

By providing a housing 34 of suitable dimensions and a light source 36 in a suitable location behind the rods, it then will be possible to cast on the work a series of spaced reference shadow lines which are one-half inch wide, separated by light lines which are 4 inches wide, all extending the entire width of the veneer sheet.

OPERATION The operation of the herein described apparatus, as applied to the casting of shadow reference lines on the upper surface of a traveling sheet of plywood veneer is as follows:

A continuous strip of veneer cut by knife 12 from log on a plywood lathe is conveyed by conveyer 16 past an operators station 0 and thence to a plywood clipper 22. In transit, it passes beneath a light box 30 located at the operators station.

The light box contains a source of light 36 and a plurality of parallel bars 66 arranged laterally, transversely with respect to the veneer sheet. The rods are mounted on chains 42, 42a which are driven by means of a connecting chain 50 driven synchronously with the conveyer drive. Accordingly, by maintaining pro-per ratios, the speed of the shadow lines cast by rods 66 will be the same as the speed of the veneer.

This affords to the operator standing at station 0' the opportunity of locating precisely the leading and trailing edges of a veneer imperfection 24, FIG. 5, so that he may place reference marks 26 on the margins of the veneer. When they reach clipper 22 the reference marks trigger the operation of the clipper so that the veneer section containing the imperfection is clipped out. In this manner the cuts made by the clipper may be located very accurately and waste of veneer is minimized.

It is to be understood that the form of my invention herein shown and described is to be taken as an illustrative example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. Apparatus for producing moving shadow reference lines on work conveyed at a predetermined lineal speed on a conveyer positioned a spaced distance from the apparatus, the apparatus comprising:

(a) a shielded housing open at the side adjacent the work,

(b) flexible endless drive means mounted in the housing in a plane parallel to the direction of motion of the work,

(c) a plurality of rods mounted on the drive means in fixed, parallel relation and at a predetermined spacing to each other, substantially normal to the direction of motion of the work,

((1) a light source mounted in the housing behind the rods, with reference to the work, thereby generating shadow lines which are projected on the work, and

(e) motor means connected to the drive means for driving the same at a speed synchronously related to the speed of the work.

2. The apparatus of claim 1 wherein the flexible endless drive means comprises a pair of endless chains mounted in spaced, parallel relation to each other on opposite sides of the housing and mounting the transversely arranged rods.

3. The apparatus of claim 1 wherein the motor means comprises chain and sprocket means connecting the rod drive means to the conveyer for driving the rods synchronously with the conveyer.

References Cited UNITED STATES PATENTS 10/1950 Peery 356-23 5/1963 Bogert 356-24 US. Cl. X.R. 3 56237 

